1. Field of the Invention
The present invention provides a memory unit with sensing current stabilization, and more particularly, a memory unit with a current mirror for maintaining an input current of a sense amplifier.
2. Description of the Prior Art
A memory is a vital component in electronic products. The memory includes a memory cell array including memory units each for storing a bit of digital data and performing programming, erasing, and reading according to control signals transmitted from a word line, a bit line, and et al. A sense amplifier in a memory unit is usually provided for sensing digital data stored in a memory cell of the memory unit and generating an output signal corresponding to the digital data when the memory is reading the memory cell.
Please refer to FIG. 1, which illustrates a block diagram of a prior art memory unit 10 in a memory. The memory unit 10, including a memory cell 12 and a sense amplifier 14, stores a digital data. The sense amplifier 14 senses an output signal of the memory cell 12 through a bit line 16 and outputs a signal SAOUT accordingly. The output signal of the memory cell 12 is low for programming or high for erasing, for example. Considering high-speed operations, the current of the low-level output signal of the memory cell 12 is set to be greater than 40 μA, while the current of the high-level output signal is set to be smaller than 5 μA. Although the current of the low-level output signal of the memory cell 12 is over eight times the current of the high-level output signal, the difference between the currents is still small (<1 mA). As a result, the sense amplifier 14 may mistake in determining the output signal of the memory cell 12 in different process, voltage and temperature conditions, which may cause the current of the output signal of the memory cell 12 drifting unexpectedly.